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IMPORTANCE: Multiple SARS-CoV-2 variants have emerged over the COVID-19 pandemic. The implications for COVID-19 severity in children worldwide are unclear. OBJECTIVE: To determine whether the dominant circulating SARS-CoV-2 variants of concern (VOCs) were associated with differences in COVID-19 severity among hospitalized children. DESIGN, SETTING, AND PARTICIPANTS: Clinical data from hospitalized children and adolescents (younger than 18 years) who were SARS-CoV-2 positive were obtained from 9 countries (Australia, Brazil, Italy, Portugal, South Africa, Switzerland, Thailand, UK, and the US) during 3 different time frames. Time frames 1 (T1), 2 (T2), and 3 (T3) were defined to represent periods of dominance by the ancestral virus, pre-Omicron VOCs, and Omicron, respectively. Age groups for analysis were younger than 6 months, 6 months to younger than 5 years, and 5 to younger than 18 years. Children with an incidental positive test result for SARS-CoV-2 were excluded. EXPOSURES: SARS-CoV-2 hospitalization during the stipulated time frame. MAIN OUTCOMES AND MEASURES: The severity of disease was assessed by admission to intensive care unit (ICU), the need for ventilatory support, or oxygen therapy. RESULTS: Among 31 785 hospitalized children and adolescents, the median age was 4 (IQR 1-12) years and 16 639 were male (52.3%). In children younger than 5 years, across successive SARS-CoV-2 waves, there was a reduction in ICU admission (T3 vs T1: risk ratio [RR], 0.56; 95% CI, 0.42-0.75 [younger than 6 months]; RR, 0.61, 95% CI; 0.47-0.79 [6 months to younger than 5 years]), but not ventilatory support or oxygen therapy. In contrast, ICU admission (T3 vs T1: RR, 0.39, 95% CI, 0.32-0.48), ventilatory support (T3 vs T1: RR, 0.37; 95% CI, 0.27-0.51), and oxygen therapy (T3 vs T1: RR, 0.47; 95% CI, 0.32-0.70) decreased across SARS-CoV-2 waves in children 5 years to younger than 18 years old. The results were consistent when data were restricted to unvaccinated children. CONCLUSIONS AND RELEVANCE: This study provides valuable insights into the impact of SARS-CoV-2 VOCs on the severity of COVID-19 in hospitalized children across different age groups and countries, suggesting that while ICU admissions decreased across the pandemic in all age groups, ventilatory and oxygen support generally did not decrease over time in children aged younger than 5 years. These findings highlight the importance of considering different pediatric age groups when assessing disease severity in COVID-19.

This paper describes the hydrothermal synthesis, full characterization, and architectural diversity of three intriguingly bioactive cobalt–organic frameworks, namely, 3D [Co(HL−)2(BPY)]n·4nH2O (1), 2D [Co(HL−)2(BPE)]n(2), and 2D [Co(HL−)2(DPP)]n(3) coordination polymers, synthesized through a mixed ligand strategy using H2L(1-H-indazole-3-carboxylic acid) as a main structural block and the flexible bipyridine and its derivatives (BPY = 4,4′-bipydine, BPE = 1,2-bis(4-pyridyl)ethane, DPP = 1,3-bis(4-pyridyl)propane) as auxiliary ligand sources. Complexes 1–3were isolated as air stable and slightly soluble crystalline solids and characterized using elemental analysis, FT-IR, electrochemical technique, thermogravimetric analysis, powder X-ray diffractometer, and single-crystal X-ray crystallography. The bipyridine derivatives played key roles in defining the structural space group and dimensionality feature of the obtained networks. The abundant H-bonding and π–πstacking interactions in complexes 1–3gave rise to their intricate metal–organic structures of 3D (1), 2D (2), and 2D (3). In addition, the solutions of complexes 1–3showed profound antifungal activities against the selected strain of Colletotrichum musaecompared with the controlled group using benomyl as a traditional agrochemical fungicide.

Based on the issue of the Corona Loss that generated in EHV and UHV transmission process, the work is about energy saving, emission reduction, and creates a kind of electric-corona-prevent paint which is suitable for both the super high pressure transmitting wires and metal equipment . The paint is consisted of RTV, charcoal and other additives. The basic theory is to cover the wires which are certain degree damaged with the paint by spraying. After that, we carry out some experiments on the covered and uncovered wires to contrast the loss of electric-corona. The results of the experiments show that, the wire covered by the electric-corona voltage and a lower loss of electric-corona than those without the paint, which proved the effect of the electric-corona-prevent paint well.

For many government departments or enterprises to use new system upgrades, data transfer between heterogeneous database problem, this paper puts forward a kind of heterogeneous database based on XML and middleware model of data migration.The model by using XML technology to build a middleware, through the ODBC interface connected to the source database and target database.After extracting data from the source database into a unified XML documents, again according to the mapping relationship between old and new database and XSL document, and converts it to meet the needs of the target XML document, the target database and load the data to the target database.The model including data extraction, transformation, validation, write, and other functions, is a cross-platform, easy extensibility and reusability.

Face the reality application in the "information island" problem, based on the analysis of the data exchange between heterogeneous database conflict, on the basis of this paper proposes a data exchange model in XML as middle format. Make full use of the XML is easy to extend, good interactivity and semantic is strong, can be formatted, easy processing, has nothing to do with the platform, and other features and advantages, and USES the c # language and XML and related technologies of the model carried on the detailed design and implementation of the main modules, and each function module in the model are relatively independent and extensible, strong commonality.

Component library as a component of assets classification and management of infrastructure becomes more and more important, in the practice of component quantity increasing, component is updated according to the technology and the field evolution, to search for suitable in numerous artifacts climb hydrophobic component must establish the effective component of said mechanism and the feasible component library management system. Business component is a fusion of business objects and components, is a business object software realization of the autonomy of business concepts and reusable software unit. An ordered set of business component, constitute the basis of the actual business activities. This paper proposes a framework based on component representation method, and put forward the major methods based on the use of business component to adapt to the change of the process, so as to realize the reorganization of business processes.

In this paper, we study for the theory of component technology and the workflow technology and method of component composition of component and component library, based on the principle of workflow technology and the component composition technology, the method to study and put forward the component assembly based on workflow technology system structure. Using this method to separate business process logic and business process implementation, under the condition of without modifying the specific function component, by redefining process model to accomplish system function change or improvement of system performance, make the enterprise can according to the business process dynamically build enterprise information system, changed the enterprise's business and process to adapt to the traditional software development model.

Moodle is a completely free open source course management system, according to the basic principle of pedagogy related; it aims to help teachers to create a effective learning community. Moodle platform used in the computer specialized curriculum teaching, enables students from the inquiry learning, autonomous learning, cooperative learning and so on several aspects to improve the effectiveness of professional course teaching. And interactive evaluation as an important component of Moodle teaching platform, directly affects the network curriculum teaching effect and quality.

A model of emotional interaction agents in intelligent tutoring systems is presented in this paper, and the functionalities of the key components of the agents are described. To improve the emotional interaction between learners and the system, a kind of emotional interaction agents which can deduce users emotional statues, provide helps needed, and mark emotional difficulty of the learned pedagogical units, is introduced and discussed in detail in order to improve pedagogical effects.

Automatic subjective question of marking is a key technology in the network test system. In order to solve this problem, this paper analyzes the grading teachers thinking reviewers subjective questions. Then introduce the concept of a one-way approach degree based on the nearness theory of fuzzy mathematics. Finally design a subjective question automatic scoring algorithm and give a specific algorithm achievement. It provide certain reference value of automatic scoring of subjective questions.

n the security monitoring system, in order to realize the multi-angle and different positions of the camera monitoring the camera monitoring, a pan tilt zoom (PTZ) module is used. This paper describes the PELCO-D protocol of PTZ and serial communication firstly. Then it achieves control the of PTZ and lens work based on Windows VC++. Finally, It discusses the main function of the system structure and coding.

this paper analyzes the problems of heterogeneous databases in a distance education system. It provides a heterogeneous database integration model based on XML and design and develop a heterogeneous database integration platform based on this model. Thus, it provides a unified standard and effective tool for teaching resource description and management in distance education.

Grid technology has become the computer and network technologys research hotspot and frontier, Grid technology development and the consummation will promote the development of educational information. The intelligent has shortcoming which are resource isolated, update difficulty etc, Based on the grid technology research and application, using OGSA (Open Grid Services Architecture) grid system structure, Taking GLOBUS as the grid middleware to build grid platform. This paper discuss the educational grid minimum implementation unit - - teaching system of campus grid and put forward the network teaching system model based on the grid technology. Then establish a distributed, heterogeneous sharing information resources of the library, it provides an efficient, fully shared virtual teaching space for network tutoring system. Finally, intelligent network teaching system and the grid binding laid certain foundation.

Note CO2 gas development has become a very effective reservoir mining method in low permeability oilfield of Daqing outskirt. It can effective enhance the recovery ratio. When the crude oil dissolves CO2, the volume expands and the viscosity decreases. Under the same conditions of temperature, expansion increases with pressure, CO2 drive is more effective than a single water drive, the degree of reserve recovery has been significantly improved, generally 1.3-1.4 times. Field tests shows that the input-output ratio in swallowing- spitting test of CO2 producing in formation could reach 6.25.

Analysis on monitoring data during construction of Chang Jiang Crossing Campaign memorial, the nonlinear method is used to get the fitting curve of stress-strain relation during construction, and the concrete constitutive relation of this project is acquired.

Abstract: The distribution characteristics of the impact craters can provide a large amount of information on impact history and the lunar evolution process. In this research, based on the digital elevation model (DEM) data originating from Change’E-1 CCD stereo camera, three automatic extraction methods for the impact craters are implemented in two research areas: direct extraction from flooded DEM data (the Flooded method), object-oriented extraction from DEM data by using ENVI ZOOM function (the Object-Oriented method) and novel object-oriented extraction from flooded DEM data (the Flooded Object-Oriented method). Accuracy assessment, extracted degree computation, cumulative frequency analysis, shape and age analysis of the extracted craters combined display the following results. (1) The Flooded Object-Oriented method yields better accuracy than the other two methods in the two research areas; the extraction result of the Flooded method offers the similar accuracy to that of the Object-Oriented method. (2) The cumulative frequency curves for the extracted craters and the confirmed craters share a similar change trajectory. (3) The number of the impact craters extracted by the three methods in the Imbrian period is the largest and is of various types; as to their age earlier than Imbrain, it is difficult to extract because they could have been destroyed.

Carbon coating is an important technique used to improve the electrochemical performance of many electrode materials in lithium-ion batteries. In the present work, was selected as the probe material and a series of carbon-coated samples was prepared to discuss the effects of graphitization and thickness of the coated carbon layer on its rate capability for lithium-ion intercalation. The apparent diffusion coefficient and rate capability were studied by cyclic voltammetry experiments using a powder microelectrode. The results show that a higher carbon coating temperature could promote the graphitization of the surface carbon, thus enhancing the electronic conductivity of the electrodes while hindering the lithium-ion diffusion. The thickness of carbon layer is demonstrated to have a major influence on ion diffusion while slightly affecting the electronic conductivity. Considering both the electronic conductivity and ion diffusion in the carbon layer, an optimal condition for carbon coating to achieve a good rate capability is determined to be performed at with a thickness of ca. .

The electrochemical profile of oxygen-deficient in both aqueous and nonaqueous electrolyte was extensively investigated. exhibited better cyclic capability in 0.5 M aqueous electrolyte than nonaqueous electrolyte. The cycling stability in the aqueous electrolyte is critically dependent on the pH value and charge cutoff potential. The difference in cycling stability between various electrolytes was demonstrated to be due to the oxidation of Mn on the surface of electrode by active oxygen atoms. X-ray photoelectron spectroscopy demonstrated that the Mn oxidation state of after cycling in aqueous electrolyte increased from 3.44 to 3.64. The amounts of oxygen atoms generated on the surface of electrode were estimated from the graphical representation of the Tafel plots.

The generalized one-dimensional Fokker-Planck equation is analyzed via potential symmetry method and the invariant solutions under potential symmetries are obtained. Among those solutions, some are new and first reported.

With the assistance of the symbolic computation system Maple, rich higher order polynomial-type conservation laws and a sixth order t/x-dependent conservation law are constructed for a generalized seventh order nonlinear evolution equation by using a direct algebraic method. From the compatibility conditions that guaranteeing the existence of conserved densities, an integrable unnamed seventh order KdV-type equation is found. By introducing some nonlinear transformations, the one-, two-, and three-solition solutions as well as the solitary wave solutions are obtained.

The palaeo-mobile dune sands and fluvio-lacustrine facies with palaeosols in Milanggouwan stratigraphic section of the Salawusu River valley situated at the southeast of the Mu Us Desert experienced abundant remarkable alternative changes of coarse and fine rhythms in grainsize since 150 ka BP, and the grain-size parameters — Mz, σ, Sk, Kg and SC/D also respond to the situation of multi-fluctuational alternations between peak and valley values. Simultaneity the grainsize eigenvalues — ϕ5, ϕ16, ϕ25, ϕ50, ϕ75, ϕ84 and ϕ95 are respondingly manifested as greatly cadent jumpiness. Hereby, the Milanggouwan section can be divided into 27 grain-size coarse and fine sedimentary cycles, which can be regarded as a real and integrated record of climate-geological process of desert vicissitude resulted from the alternative evolvement of the ancient winter and summer monsoons of East Asia since 150 ka BP.

Abstract: We have analyzed the Mssbauer spectra of a highly anisotropic low-spin ferric compound, [Fe(TICOH)2](BF4)3, taken in frozen solution as a function of temperature and field. Unlike other low-spin ferric compounds, [Fe(TICOH)2](BF4)3 shows a sharp six-line pattern with an overall s;litting of 14.2 mm/s in an applied field at 4.2 K. Good simulations are obtained using the model of Oosterhuis and Lang with a crystal field of axial symmetry. At higher temperature spin fluctuations become important, and a dynamic lineshape model with temperature- and field-dependent relaxation rates is used to simulate the data.

In this paper, from the perspective of XML data management, first in the HDFS store large amount of data and XML data based on XML data query rewrite the traditional framework of MapReduce process, the design of large amount of data XML data set keywords retrieval algorithm, contain XML data classification and coding, index and search a four parts, solve the large amount of data of the XML document keywords retrieval problem. Then the design and implementation based on MapReduce of large amount of data XML keyword query system.

This article aims at the geology situation of Hai-la-er area, researches the influence factors of the quality of well cementation in the Hai-la-er area., establishes, improves and perfects the improvement measures of enhancing the quality of well cementation in the Hai-la-er area, and also produces notable effects in the filed test. In 2004, there were 11 well cementations in all and 5 of them were of high grade. The average sealing section was 1537 meters, and the factor of merit was 45.45%.

The article suggests that the limitation of the traditional value orientation of competitive sports is merely serving politics and is ignoring the needs of individual development in China. It further suggests that the value of competitive sports is the combination of social and individual value. The article shows that current research focus on how to promote competition performance and do not solve the problem of how to upgrade the traits of competitive sports into modern ethical quality.